1. Field of the Invention
The present invention relates to a method and to a device for testing the design of a seat comprising a seat area, a backrest, and a headrest. On the substantially horizontally oriented seat area, a substantially vertically extending backrest is arranged on the rear edge, the backrest being either fixed to or adjustable around an angular section. The upper edge of the backrest has arranged thereon an adjustable headrest having bars that are shiftable in headrest exit openings in the backrest. The distance of the headrest from the upper edge of the backrest is variable so that the headrest can be adjusted to a passenger's size. In some seat models, the inclination of the headrest relative to the horizontal is adjustable by way of a pivotable movement of the headrest, so that the distance between the front side of the headrest and the back of a passenger's head is adjustable. The clearance between headrest and passenger's head is also called backset and also depends on the design of the seat. Since the distance between head and headrest is a decisive safety criterion, seats are checked within the scope of quality assurance with respect to their design.
2. Description of the Related Art
A manual method for performing the backset measurement is known, in which a dummy that is to simulate a passenger's size and height is put under specific conditions on the seat to be tested. This procedure is force- and time-consuming. The dummy is provided in the center of its head with a probe that consists of a rail extending in the direction of travel and of a ball segment arranged on the rear end thereof, which is to simulate the back of a head. To measure the backset, the probe is moved to the headrest and the distance is read by an operator from a ruler positioned on the rail. The manual backset measurement is only carried out by taking random samples, so that the design of the seat in consideration of manufacturing tolerances can only be carried out in an inadequate manner. The reason is that, apart from the constructional design, manufacturing tolerances also influence the final design of a seat leaving the production process.